I just read in another benz site, someones thread reguarding viscosity being answered by a race car driver who warned about motor oils with big gaps between viscosity such as 5 - 40, and in particular M-1 15 - 50 that it is a better oil that has closer viscosities such as 10 - 30. I'll have to go back and read it again, but he claims the wider the spread the less lubricating quality!

Any one heard anything about this?